Woodlice: Why Your Terrarium Needs Them

Woodlice are ubiquitous. These small, armored animals are super suitable for a closed terrarium. Not only are they very cute for creepy crawlies, but they also play an important role in maintaining the ecosystem in your closed terrarium. In this article, we'll look at what exactly makes woodlice so important and how you can keep them in your closed terrarium.

We'll start with some general information about them first, and then look at how they help stability in your closed terrarium.

If you want to read a general overview of animals in closed terrariums, I recommend this article on 6 types of animals for a closed terrarium.

What are woodlice?

Closed Terrarium Animals Woodlice
A common gray woodlouse. Source: Dat doris on Wikimedia Commons, CC BY-SA 4.0

Woodlice (Porcellio scaber) are not insects, even though they may look like it at first. Unlike, for example, springtails (which are also not insects), they don't even have six legs. More on that in a moment. Strictly speaking, woodlice belong to the terrestrial isopods (Oniscidea), which in turn are a subgroup of crustaceans (Isopoda). Translated with www.DeepL.com/Translator (free version)

Terrestrial isopods are the only crustaceans that live permanently on land. This distinguishes them from land hermit crabs. The latter live on land most of the time, but must return to the water to reproduce. There they lay their eggs.

In total there are about 3500 species of terrestrial isopods. Just 50 of them live in Germany (where I live). But that shouldn't bother us at all, because the little rascals are fortunately not rare.

Body structure of woodlice

All woodlice have a dorsal carapace of chitin. In most of them this carapace is colored gray. However, there are also red isopods, which are not seen very often. As mentioned, they do not have six legs, but up to 28 legs, or 14 pairs. However, they are not all meant for walking.

Red woodlouse closed terrarium
There are also red woodlice. Source: piqsels.com

Seven pairs are so-called walking legs with which they walk. Five pairs are leaf legs and one pair are so-called uropods, which are not suitable for walking. These are still remnants from prehistoric times. To be quite honest with you, I'm not sure about the leaf legs. That's what they're called in German but there is no English Wikipedia article on it. If you know more than me, let me know.

By the way, woodlice cannot completely curl up into a ball. It is true that they go into rigor mortis in the event of danger and curl up under their shells. Only the common woodlouse can curl up into a ball.

The many names of woodlice

There are an incredible amount of names for woodlice. Some of my favorites are monkey-peas, fat pigs, carpet shrimp and of course the infamous roly-poly. You can read many names on Wikipedia here.

Their scientific name Porcellio scaber literally means something like rough, unclean piglet. That sounds kind of cute and also quite appropriate.

What do woodlice eat?

Woodlice feed on so-called detritus. This is dead, organic material. This can be, for example, plants or other insects or their excrements. Woodlice do not hesitate.

Due to their eating habits, woodlice are also counted among the so-called sacrophages. This has not directly something to do with sarcophagi, but there they would probably also feel quite comfortable. Generally speaking, they hang around where things rot. Other sacrophages are for example maggots or worms.

However, woodlice also like to eat fresh fruits and vegetables. Potatoes are often on their menu. Thus, woodlice are also considered a pest, because they eat away our stored food. But can you really be angry with the little ones? After all, they are just hungry. We would probably do the same!

Detritus dead plants with sticks and pine cones
Dead plant materials are called detritus. Source: Walter Siegmund on Wikimedia Commons, CC BY 2.5

Basement woodlice as ground police for a closed terrarium

That they eat dead materials is extremely important for a closed terrarium! In the article about substrates I have already pointed out that plants cannot live indefinitely. At least, not all plants can. Orchids, for example, can.

Since plants also have a maximum life span, you will inevitably have plant debris in your closed terrarium at some point. However, this should not just be left on the floor, otherwise a solid layer will form on your substrate, on which standing water can collect. This will cause lasting damage to your plants.

This is where the good woodlice come in. They prefer to eat the dead plant material in your closed terrarium and are also much faster than, for example, springtails or snails. Their droppings can easily be reabsorbed by your substrate, giving you a natural fertilizer for your plants!

A bioactive substrate is the best foundation for a terrarium that really lasts forever.

Where can you find woodlice?

Now that we've talked so much about them, we still need to know where to get them from.

You can find them in your basement, in the garden or in the forest. They prefer damp, dark corners. For example, if you find a large piece of dead wood and turn it over, you're sure to find a few woodlice that you can carefully take with you.

Group of woodlice on a tree bark
Woodlice like to hang out in dark corners. Source: Hans Hillewaert on Wikimedia Commons, CC BY-SA 4.0

Alternatively, you can also buy woodlice online. There you'll have a larger selection. There are probably more beautiful woodlice than you might think at first. Another article about different types of woodlice will follow on the Terrarium Blog.

How to keep woodlice in a closed terrarium

Keeping woodlice in a closed terrarium is easy as pie. You start by putting in a few of the crawlers and just have to make sure they have enough to eat and that it doesn't get too warm for them. They should also have a place to hide.

It is true that woodlice prefer to eat detritus. However, they will not shy away from feeding on your live plants if there is nothing else available. You can help them by putting some dead wood and a few leaves in your closed terrarium. This does not have to be a lot, because the small woodlice do not eat that much.

Woodlice prefer it cool and humid. So please do not place your closed terrarium in the blazing sun. The greenhouse effect will cause it to heat up very quickly. Indirect light, however, does not bother them. Nevertheless, you should decorate your closed terrarium in a way that the woodlouse can retreat to a shady place. This can be, for example, a large piece of wood or a small cave made of stones.

In most cases, your closed terrarium will already have suitable humidity for woodlice. To learn how to provide the right amount of water in a closed terrarium, see this article.


Woodlice are important for maintaining order in your closed terrarium. They support the ecosystem by eating dead plants and making a natural fertilizer out of them through their excretions. Keeping woodlice in a closed terrarium is quite simple and requires little special measures. You just need to make sure they have enough food, don't put them in direct sunlight and build a place for them to hide.

Also great for a bioactive closed terrarium are springtails. In the article about springtails in a closed terrarium you will learn everything about the tiny long jumpers.

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